Modular sand and dust environmental testing system

ABSTRACT

A portable environmental testing system for environmental testing with particulate matter, such as sand and dust, is disclosed. The components of the system are largely contained within a modular container, such as an intermodal shipping container. The testing system uses a feeder to feed precise amounts of particulate matter into an injector, which injects the particulate matter into an airflow that leads to a nozzle assembly. The airflow itself is generated by a compressed air system. The material input station, for inputting particulate matter, includes operator protection features, like a negative draw fan. The system may be provided with wheels and a tow bar.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 14/253,643, filed Apr. 15, 2014, now U.S. Pat. No.9,677,991, which is a divisional of U.S. patent application Ser. No.12/958,132, filed Dec. 1, 2010, now U.S. Pat. No. 8,733,186, whichclaims priority to U.S. Provisional Patent Application No. 61/266,052,filed Dec. 2, 2009. This patent application also claims priority to U.S.Provisional Patent Application No. 62/400,239, filed Sep. 27, 2016. Thecontents of all of those applications are incorporated by referenceherein in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to environmental testing systems, and moreparticularly, to environmental testing systems capable of exposing atest piece to sand and dust.

2. Description of Related Art

Many pieces of equipment are subjected to environmental extremes duringtheir service lifetimes. Those environmental extremes may be, forexample, extremes of temperature, pressure, vibration, acceleration, orshock. Equipment may also be subjected to environmental conditions suchas rain, wind, sand, dust, and humidity, to name a few. Theseenvironmental conditions can shorten the operational lifetime of a pieceof equipment or cause it to fail entirely.

Over time, various methods have evolved for testing equipment todetermine whether it can withstand various environmental extremes andconditions, and if so, what effect those extremes might have on theequipment. Most of these methods involve placing the equipment inquestion in an environmental test chamber that is equipped to simulatethe desired environmental extremes.

Environmental testing techniques and methods are used widely inindustry, both to certify that equipment will not fail under particularconditions and to evaluate the nature and reproducibility of failuresthat do occur. However, because resistance to environmental extremes isparticularly important in the case of military equipment, a number ofmilitary organizations have produced standards documents that define howdifferent types of environmental tests are to be performed. In theUnited States, MIL-STD-810G, “Department of Defense Test Method Standardfor Environmental Engineering Considerations and Laboratory Tests”contains military standards for a variety of different types ofenvironmental testing. Among the methods covered by MIL-STD-810G aremethods for sand and dust environmental testing.

In a typical sand or dust environmental test, a piece of equipment isplaced in a test chamber, and the test chamber is heated to an elevatedtemperature, e.g. 180° F. (82° C.). Either sand or dust is blown intothe chamber continuously for the duration of the test, which typicallylasts about ninety minutes.

Test systems for performing sand or dust environmental testing do exist,but these systems do have a number of difficulties. First and foremost,these systems can have difficulty producing a laminar airflow into theenvironmental testing chamber that has an even distribution of dust orsand particles, all of which are moving at essentially the samevelocity. Moreover, in some of these systems, the air mover or blowerthat creates the airflow into the test chamber is directly exposed tothe sand or dust, which can cause wear and reduce the effectiveness ofthe blower.

Finally, sand and dust may be hazardous to human health. Sand inparticular can cause silicosis, a serious lung condition, if it isinhaled. For that reason, it is important to protect the operator of asand and dust environmental testing system from exposure to the sand anddust.

SUMMARY OF THE INVENTION

One aspect of the invention relates to an environmental testing system.The environmental testing system is designed for environmental teststhat expose test pieces to particulate matter, typically either sand ordust, entrained in an airflow. In the environmental testing system, ablower creates the airflow that recirculates through the system. Theblower is arranged relative to a filter chamber such that it is on the“clean” side of the system and is not exposed to the particulate matter.The system also has a particulate matter feed mechanism that includes afeeder that feeds measured amounts of particulate matter to an injector,which injects the particulate matter into an inlet duct with a velocitythat at least substantially matches the velocity of a surroundingairflow in the inlet duct. The inlet duct is connected to the inlet ofan environmental test chamber. In some embodiments, the feeder may be aloss-in-weight gravimetric feeder, and the injector may be a Venturivalve.

Another aspect of the invention relates to operator protection systemsfor an environmental testing system. In a system according to thisaspect of the invention, the environmental test chamber includes anoutlet that is coupled to an exhaust fan and filter elements. Theexhaust fan may also be coupled to a particulate matter input station,where particulate matter is introduced into the system. When the door ofthe environmental test chamber is opened, or when particulate matter isintroduced into the system, the exhaust fan is activated to create anegative pressure, drawing any particulate matter away from the user.

Yet another aspect of the invention relates to material handling andconveying systems for environmental testing systems. In environmentaltesting systems according to this aspect of the invention, a pneumaticconveying system, including a pump and a network of pipes, are used toconvey fluidized particulate matter into the system. A series of gatesor valves are provided in the network of pipes such that the samepneumatic system can be used to collect used particulate matter anddirect it in fluidized form either back to the feed system for re-use orto a waste hopper for disposal.

Additional aspects of the invention pertain to methods of controllingparticulate matter environmental testing systems to maintain particulartemperatures and other test conditions during an environmental test.

Yet another further aspect of the invention relates to portable systemsand methods for sand and dust environmental testing. In a systemaccording to this aspect of the invention, components adapted to supplyprecise amounts or concentrations of particulate matter entrained in asupply of compressed air are installed in a portable container, whichmay be a modular container, such as an intermodal shipping container.Within the container, for example, a material input station, aparticulate matter feed mechanism, and a compressed air generatingsystem may be installed for operational use, along with other operatorprotection features. An outlet may be provided on the exterior of thecontainer that leads to appropriate piping and a nozzle. The containeritself is easily transported by ship, rail, or truck chassis, and canalso have wheels and a tow bar mounted for handling once it arrives at asite where tests are to be conducted.

These and other aspects, features, and advantages of the invention willbe set forth in the description that follows.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention will be described with respect to the following drawingfigures, in which like numerals represent like features throughout thedrawings, and in which:

FIG. 1 is a front perspective view of a sand and dust environmentaltesting system according to one embodiment of the invention;

FIG. 2 is a rear elevational view of the testing system of FIG. 1;

FIG. 3 is a top plan view of the testing system of FIG. 1;

FIG. 4 is a simplified, schematic front elevational view of the testingsystem of FIG. 1 in partial cross-section, illustrating the main airflowwithin the system during a test;

FIG. 5 is a cross-sectional view of the upper ducts of the testingsystem of FIG. 1, illustrating the heating and cooling mechanisms;

FIG. 6 is an elevational view of the particulate injection mechanism ofthe testing system of FIG. 1 in isolation;

FIG. 7 is an elevational view of the particulate loading mechanism ofthe testing system of FIG. 1 in partial section, showing how particulatematter is conveyed;

FIG. 8 is a perspective view of particular components of a pneumaticconveying system for sand and dust, shown in isolation;

FIG. 9 is a flow diagram of the tasks involved in conducting a sand ordust environmental test using the testing system of FIG. 1;

FIG. 10 is a perspective view of a modified intermodal shippingcontainer containing a complete sand and dust delivery system;

FIG. 11 is an interior perspective view of the container of FIG. 10; and

FIG. 12 is an elevational view of a particulate feeder in isolation.

DETAILED DESCRIPTION

FIG. 1 is a front perspective view of a sand and dust environmental testsystem, generally indicated at 10, according to one embodiment of theinvention. The testing system 10 is designed to expose a test piece tohigh-velocity airstreams with entrained sand or dust at elevatedtemperatures, in order to determine what effect those conditions have onthe test piece. The testing system 10 may be constructed to performtests according to recognized standards, such as the test methods setforth in MIL-STD-810G, although that need not necessarily be the case.

The testing system 10 includes an environmental chamber 12 into whichthe test piece (not shown in FIG. 1) is placed for testing. An airhandling system, generally indicated at 14, creates the airflownecessary for the test, filters the particulate matter out of the air,and recirculates the air continuously during the test. The air handlingsystem 14 comprises, among other components, a blower housing 16, wherethe blower or air mover is located; a delivery duct 18 that leads intothe environmental test chamber 12 and into which the sand or dust isinjected as the airstream flows past; a filter chamber 20, where thesand or dust is filtered from the airstream; and a set of upper ducts22, 24, which direct the filtered air back toward the blower housing 16and also contain a temperature control system. The temperature controlsystem and methods of heating and cooling the air will be describedbelow in more detail.

FIG. 2 is a rear elevational view of the testing system 10. In additionto the air handling system 14, the testing system 10 includes aparticulate delivery system 26, which feeds precisely defined amounts ofsand or dust into the delivery duct 18. A compressed air system 28,including a compressor 30, a compressed air tank 32, and an air dryer34, is used by the particulate delivery system 26 and by certain othersystems, as will be described below in more detail. A particulatematerial handling system, including a material input station 36, a feedhopper 38, and a waste hopper 40 (shown in FIG. 1) connected byappropriate piping, is used to introduce sand or dust into the system10, move the sand or dust into position to be injected into the deliveryduct 18 by the particulate delivery system 26, and move the sand or dustout of the system 10 after use.

The overall process of a test is controlled by a computing system 42,which, in the illustrated embodiment, comprises a programmable logiccontroller (PLC), such as an Allen-Bradley PLC. In other embodiments,other types of computing systems may be used, including general purposecomputers. In the illustrated embodiment, the interface with thecomputing system 42 is by means of a touch screen display 44 (shown inFIG. 1), although keyboards, mice, and other conventional input/outputdevices may be used.

Air Handling and Flow

FIG. 3 is a top plan view of the testing system 10, and FIG. 4 is asimplified schematic view of the airflow through the system. As shown inFIG. 4, air flows in a basic loop around the system, and is recirculatedthroughout a typical test. The airflow loop begins at the air mover orblower 46, which is mounted horizontally for rotation along a verticalaxis of rotation within the blower housing 16.

The blower 46 may be any type of blower or air mover capable ofproducing the airspeeds and volumes used in a sand or dust environmentaltest, and depending on the type of blower, it may be mounted verticallyor horizontally. The blower wheel or fan itself may be made of anysuitable material, although it may be advantageous if the blower wheelis made of a non-sparking material, such as aluminum. The blower 46 ofthe illustrated embodiment is driven by a motor 48. It is advantageousif the motor 48 is capable of variable speeds, so that the blower 46 maybe driven to move air at speeds between, for example, 1500 feet perminute (FPM) (17.3 miles per hour (MPH)) and 5777 FPM (65.6 MPH). Themotor 48 may have, for example, a rated power of 150 horsepower and mayinclude its own cooling system, such as a fan cooling system, and otherconventional subsystems not shown in FIG. 4.

Although portions of this description may refer to a single main blower,embodiments of the invention may use more than one blower, arrangedeither in series or in parallel, in order to create the necessary airflow. With multiple blowers, each of the individual blowers may beconsiderably smaller than a blower 46 of comparable capabilities. Forthat reason, multiple blowers may be particularly useful in situationsin which the physical space available for system 10 is limited. As thoseof skill in the art will realize, placing blowers in parallel increasesthe volume of air flow in the system; placing them in series does notchange the volume but does increase the pressure. If used, multipleblowers could be co-located in a single housing, or individual blowerscould be located in different locations around the airflow loop.However, as will be described below in more detail, it is advantageousif the blower 46 or blowers are on the “clean” side of the airflow loop.

The blower housing 16 may be sound insulated with appropriatethicknesses of soundproofing materials so as to reduce ambient noisefrom the blower 46. Additionally, the blower housing 16 and all otherelements of the testing system 10 would generally be thermally insulatedin order to maintain the airflow at the temperatures desired for anenvironmental test.

As will be described below in more detail, in the testing system 10, theblower 46 is on the “clean” side of the airflow loop. In other words,air with entrained sand or dust does not pass through the blower 46.This may reduce wear and tear on the blower 46. Additionally, it may bea significant advantage over environmental testing systems in which airwith entrained sand or dust does pass through the blower. Withoutintending to be bound by any particular theory, it is believed thatabrasive sand passing through a conventionally-arranged blower may wearthe blower and shorten its lifetime. The wear may also alter the surfacearea of a conventionally-arranged blower's blades, thus decreasing theflow and velocity of the air and entrained particulate matter.Conventional systems may or may not be able to register and compensatefor these blower erosion problems, thus leading to inaccurate testresults and repeatability problems. By contrast, the arrangement shownin FIG. 4 avoids these problems.

From the blower housing 16, the airflow passes into and through thedelivery duct 18. The delivery duct 18 is generally rectangular in shapeand interior cross-sectional area, and is the portion of the airhandling system 14 where particulate matter, in this case either sand ordust, is introduced into the airflow. In some embodiments, the deliveryduct 18 may include static neutralizing vanes upstream of the point atwhich the sand or dust is introduced. Alternatively, these staticneutralizing vanes may be arranged at or near the exit to the blowerhousing 16. These static neutralizing vanes would be connected to thecompressed air system 28 and would use compressed air and appropriateelectrical circuitry to create a stream of ionized airflow that tends toreduce or eliminate static electricity.

From the delivery duct 18, the airflow passes into the environmentaltest chamber 12 itself. The environmental test chamber 12 wouldtypically have sufficient dimensions such that a piece of equipment ofconsiderable size can be tested. For example, in one embodiment, theenvironmental test chamber may be six feet high, six feet wide, andeight feet long. It may be constructed of a metal, such as steel oraluminum, insulated along the exterior with thermal insulation, such asglass fiber insulation. A hinged door 50 with a clear, transparentwindow 52 for viewing is hingedly attached to the front of theenvironmental test chamber 12. In some embodiments, a staticneutralizing system may be provided on the interior of the door 50proximate to the window 52, in order to prevent the window 52 from beingobscured by statically-adhered sand or dust during a test. Theenvironmental test chamber 12 may also have an interior lighting systemto facilitate viewing of the test piece during a test.

The environmental test chamber 12 will typically include some kind ofsupport 54 on which a test piece is to be placed for testing. In oneembodiment, that support may be, for example, a 54-inch by 54-inch steelgrate table capable of supporting up to 2,000 total pounds of weight.Although solid tables and supports may be used, the use of grate tablesor tables with other types of openings allow sand and dust to falldownwardly, through the support 54, once the particles have impacted thetest piece. In other embodiments, the support 54 may be round or of anyother suitable shape.

The support 54 may optionally be mounted on a motor 56 for rotation, sothat the test piece can be rotated during the test without having topause the test and open the door 50 to the environmental test chamber12. The rotation of the support 54 would generally be under the controlof the computing system 42. Depending on the nature of the test, thesupport 54 may be directed to rotate continuously in 360° circles, orthe computing system 42 may be programmed to rotate the support 54 inincrements over specific time intervals during the test. In someembodiments, the motor 56 may be controlled simply by turning its powersupply on and off. In other embodiments, the motor 56 may be a steppermotor or another type of motor that can be directly electricallyaddressed and controlled. Most embodiments of the invention will includeeither a motor 56 capable of recording and communicating the angularposition of its shaft to the computing system 42, or alternatively, aseparate angular position sensor on the shaft on which the support 54 ismounted.

The presence of a rotatable support 54, although optional, providescertain advantages. With such a rotatable support 54, users caninvestigate not only the overall effect of sand, dust, and temperatureon a test piece, but also the effects of changing the angle of attack ofthe sand and dust. For example, by rotating the test piece, users canestablish whether a particular part, side, or aspect of the test piecewears or reacts more strongly to the environmental conditions than otherparts. If the angular position of the support 54 is monitored andrecorded, the user can more easily determine whether a failure of aparticular side or aspect of a test piece is repeatable.

As shown in FIG. 4, the bottom 58 of the environmental test chamber 12has the general shape of an inverted pyramid, which allows any particlesthat may fall toward the bottom of the chamber 12 to be collected in amanner that will be described below in more detail.

At the rear of the environmental test chamber 12, an air outlet and aseries of louvers 60 covering the air outlet are provided. The louvers60 are controlled by the computing system 42 that controls the testingsystem 10 and provide a pathway for air to move out of the environmentaltest chamber 12 and the testing system 10. That pathway is used, and thelouvers 60 are opened, for a number of different reasons.

As can be appreciated from the rear elevational view of FIG. 2, the backof the chamber 12 where the louvers 60 are located abuts and shares awall with the material input station 36. The interior of the materialinput station 36 contains a number of canister-type filters 62 (bestseen in the view of FIG. 7), which lie upstream of an exhaust fan 64 atthe top of the material input station 36. Just upstream of the exhaustfan 64 is a secondary filter element, such as a high efficiencyparticulate air (HEPA) filter (not shown in the figures). Therefore,when the louvers 60 on the back wall of the environmental test chamber12 are open, it creates an airflow pathway through the canister filters62 of the material input station 36, through the secondary filter, andout to the surrounding air through the exhaust fan 64. The exhaust fan64 is generally much smaller than the main blower 46, but should besized to create a substantial draw, such as a 200 FPM draw. The canisterfilters 62 and secondary filter may filter the escaping air to, forexample, 99.96% at 2.5 micron size. As those of skill in the art willrealize, the particular types of the filters are not critical, so longas they are suitable for the application.

The airflow pathway created by the interaction of the louvers 60 and thematerial input station 36 can be used for two main purposes. First, thedoor 50 to the environmental test chamber 12 may be equipped with anelectrical switch, such that its opening can be detected. When the door50 is opened, the louvers 60 are opened and the exhaust fan 64 started,creating a negative pressure draw within the environmental test chamber12. This negative pressure draw is used to protect the operator—any sandor dust that may be in the chamber 12 when the door 50 is opened isdrawn out and away from the operator and is filtered before beingexhausted. This may be of particular use at the end of a test, whenthere may be a substantial accumulation of particulate matter in thechamber 12. Of course, the exhaust fan 64 may also be manually activatedby a separate switch or through the interface 44 of the computing system42.

Additionally, the louvers 60 may be opened and the exhaust fan 64triggered during a test in order to draw air out of the airflow loop.This can be used, for example, to compensate for the expansion of theair within the system 10 as the air is heated.

In some embodiments, there may be certain advantageous relationshipsbetween the sizes and cross-sectional areas of certain components of thetesting system 10. For example, the cross-sectional area of the deliveryduct 18 and its outlet may be determined such that when there is a testpiece of maximum testable cross-sectional area in the environmental testchamber 12, there is no reduction in the overall area through which airis permitted to flow, and thus, no slowing of the incoming air.Moreover, typically, the airflow exitway 66 from the environmental testchamber 12 would have the same cross-sectional area as the delivery duct18 and its inlet, so that there is no backpressure that might otherwisebe caused by a change or restriction in the airflow path.

From the airflow exitway 66 leading from the environmental test chamber12, air moves into the filter chamber 20, where any remainingparticulate matter is stripped from the airflow. The upper portion ofthe filter chamber 20 is filled with a number of filter elements 70,which may be, for example, cylindrical “bags” constructed of aconventional filtration material, such as polyester felt. These filterelements 70 may be mounted on or suspended from a rack or racks 72. Therack or racks 72 may themselves be connected to agitator levers or knobs74 that can be actuated to agitate the racks 72 and the filter elements70 that are suspended from them. Agitation of the filter elements 70 mayclean them by causing particulate matter encrusted on them to drop tothe floor of the filter chamber 20. In some embodiments, the compressedair system 28 may be connected to the filter chamber 20 such that it candeliver bursts of compressed air to the filter elements 70 to cleanthem.

In addition to filter elements 70, mechanical obstructions, baffles, andtortuous airflow pathways may be used to separate air from entrainedparticulate matter. For example, in some embodiments, a baffle orbaffles may be located in the airflow exitway 66 or the filter chamber20 to facilitate separation. Of course, as noted above, it is preferableif the baffles are sized and arranged such that they do not createbackpressure within the environmental test chamber 12.

The bottom of the filter chamber 20 comprises a pair of bottom spaces 76that have the general shape of inverted pyramids, similar to the bottom58 of the environmental test chamber 12. Like the bottom 58 of theenvironmental test chamber 12, the bottom spaces 76 allow capturedparticulate matter to be collected.

As shown in FIG. 4, the bottom 58 of the environmental test chamber 12and the bottom spaces 76 of the filter chamber 20 are connected to acommon set of piping 78 that allows collected particulate material to bepneumatically or otherwise conveyed elsewhere.

At the top of the system 10 and the top of the airflow loop are theupper ducts 22, 24 that direct the air back toward the blower housing 16and contain the temperature control system. The arrangement of the twoducts 22, 24 is best seen in the top plan view of FIG. 3, and can alsobe seen in FIG. 5, which is a top cross-sectional view of the ducts 22,24.

Air normally flows through the main duct 22. However, a set of dampers80, 82 linked to the computing system 42 allows the flow to be directedeither into the main duct 22 or into the heating and cooling duct 24.Prior to the damper 82, the heating and cooling duct 24 includes afiltering element 84, such as a fibrous filter, and a cooling element88. Provided between the filtering element 84 and the cooling element 88is an air velocity sensor 86. Downstream from those elements in theheating and cooling duct 24 is a heating element 90, such as a resistiveheating element. In some embodiments, only a single damper 80, 82 may beprovided.

As was explained above, sand and dust environmental tests are typicallyrun at an elevated temperature. Typically, at the beginning of a test,the computing system 42 would power on the heating element 90, close thedamper 80 in the main duct 22, and open the damper 82 in the heating andcooling duct 24, thus forcing the airflow through the heating andcooling duct 24. As it circulates through the heating and cooling duct24, the airflow would be heated until it reaches a setpoint temperature,e.g. 170° F. (77° C.), at which point the heating element 90 would beshut off and the air rerouted through the main duct 22.

During the test, the temperature of the air will typically rise by adegree or two each time it passes through the blower 46, because of heattransfer and friction. Therefore, once the air in the system has reachedan initial temperature setpoint, it may not be necessary to keep theheating element 90 on during the major portion of a test. Generallyspeaking, adequate thermal insulation in the air handling system 14 andother components will be sufficient to maintain air temperature at adesired setpoint. However, in situations in which the setpoint isparticularly high or in which portions of the air handling system 14cannot be well insulated, the heating element 90 may be turned on duringthe test and the dampers 80, 82 may direct at least a portion of theairflow through it.

At various times, it may be desirable to cool the air circulatingthrough the system 10 in order to maintain a desired setpointtemperature and avoid temperature overshoot. For that reason, the damper82 can be opened, the damper 80 in the main duct 22 can be closed, andthe cooling element 88 activated. Depending on the embodiment, thecooling element 88 may comprise a refrigerant-driven cooling system, aheat exchanger, one or more thermoelectric cooling elements, a set oftubing through which chilled water flows, or any other conventionalcooling mechanism. A pipe 92 or set of pipes may be used to conveychemical refrigerant, chilled water, or other elements into and out ofthe cooling element 88, if necessary.

Of course, the act of actively heating and cooling the air in the system10 also has the effect of drying it, as moisture is forced to condenseon the cooling element 88. For that reason, in some embodiments, a drippan and appropriate piping may be used to convey condensed water out ofthe system.

Because of their drying effects, the cooling and heating elements 88, 90may be used to maintain a desired or required level of humidity in theairflow. In some embodiments, even if a test is conducted at roomtemperature, the cooling and heating elements 88, 90 may be activated sothat their effects will dry the air within the system. In otherembodiments, a separate, conventional desiccant-based system may be usedto dry the entire airflow within the system, although using the heatingand cooling system for drying is generally advantageous.

In the description above, it should be understood that although thedampers 80, 82 are referred to as being in either open or closed states,the dampers 80, 82 could be placed in partially open or partially closedpositions, such that some of the airflow would flow through the heatingand cooling duct 24.

Additionally, although in the illustrated embodiment, both heating andcooling elements are provided in the heating and cooling duct 24, insome embodiments, one element may be provided in each duct 22, 24, withthe dampers 80, 82 used to control where the air flows depending onwhether it requires heating or cooling.

Sand and Dust Delivery

Generally, tests using the testing system 10 will use either sand ordust in a single test. As was noted above, the system 10 provides aparticulate delivery system 26 capable of delivering a metered amount ofsand or dust per unit time or airflow volume into the delivery duct 18in such a way that the particulate matter injected into the deliveryduct 18 is evenly distributed and of uniform velocity by the time itenters the test chamber. The uniform velocity with which the particulatematter is injected will typically at least substantially match thevelocity of the surrounding airflow. In this description, the term“particulate matter” is used to refer to either sand or dust. In mostembodiments, the testing system 10 will handle sand and dust inessentially the same way during a test, with the exception that dust istypically recycled through the system 10, while sand is not. Of course,in some embodiments, sand may be recycled during a test. Ultimately,however, it should be understood that systems according to embodimentsof the invention may deliver any form of particulate matter.

A fluidized mixture of air and particulate matter is pneumaticallyconveyed to a separator 94, which includes its own set of filtrationelements 96. The separator 94 sits atop the feed hopper 38, such thatwhen the fluidized air/particulate matter mixture enters the separator94, the particulate matter is forced out of the airflow by filtrationelements 96 and drops down into the feed hopper 38. (The air in whichthe particulate matter was entrained is recycled through the system 10.)The filtration elements 96 are similar to others in the testing system10 (although they may be smaller and less numerous), and are mounted ontheir own rack 98, which is connected to an agitation mechanism 100 forfilter cleaning. As was noted briefly above, the compressed air system28 may also be connected to the separator 94 to pulse the filtrationelements 96 and thus remove the particulate matter from them.Additionally, as was also noted above, mechanical baffles and tortuousairflow pathways may also be used to facilitate separation.

A feeder mechanism 102 coupled to the feed hopper 38 feeds meteredamounts of particulate matter into an injector 104 which injects theparticulate matter into the airflow within the delivery duct 18. Thefeeder mechanism 102 may, for example, be a loss-in-weight gravimetricfeeder, or any other type of feed mechanism capable of feeding aspecified unit volume or weight of material in a specified unit of time.One example of such a feed mechanism is the ROTARY SCALPEL™ feedermechanism sold by 3I's Technologies, Inc. (Vineland, N.J., UnitedStates).

Several different types of injectors 104 may be used in embodiments ofthe present invention. In general, injectors fall into two categories:(1) eductor-type injectors that have separate inlets for the material tobe delivered and for the motive gas or force; and (2) single inlet andoutlet injectors. For example, a Venturi valve, one suitable type ofinjector 104, falls into the first category. Injectors that fall intothe second category, such as blast pots regulated by appropriate valves,typically have a charged or pressurized reservoir from which thematerial is fed.

The injector 104 in the illustrated embodiment is a Venturi valve. Asshown in the view of FIG. 6, the injector 104 is connected to the feedermechanism 102 and is mounted on a pipe or tube 106 that places theinjector 104 in the center of the delivery duct 18. The Venturi valve isactuated by the compressed air system 28; specifically, compressed airflows from the air dryer 34, which would typically be desiccant-based,through a pipe 108 that enters the side of the delivery duct 18 and isconnected to the injector 104. The compressor 30 and air tank 32 ensurethat the testing system 10 maintains a reserve of compressed airsufficient to actuate the Venturi valve injector 104 continuouslythroughout the duration of a typical test. The compressed air system 28may deliver, for example, sixty CFM of compressed air at eighty poundsper square inch (psi) in order to actuate the Venturi valve injector104. The pressure that the compressed air system 28 delivers may beregulated and varied to vary the velocity of the particulate matter.

Although portions of this description refer to compressed air and acompressed air system, depending on the nature and type of injector 104and the nature of the test that is to be performed, other types of gasesmay be used to provide motive force for injecting particulate matter.For example, in some embodiments, a light, inert gas, such as nitrogen,may be used instead of compressed air.

The injector 104 injects the particulate matter into the delivery duct18 such that the particulate matter entering the delivery duct 18 has avelocity that at least approximately matches the velocity of thesurrounding airflow. The position of the injector 104 in the deliveryduct may be defined by regulatory requirements, and in particular, itmay be located a defined horizontal distance (e.g., ten feet) from theentrance to the chamber 12.

Regulatory requirements that define the distance between the point ofparticulate matter introduction and the chamber 12 are typicallyintended to ensure uniform distribution and velocity of the particulatematter as it enters the chamber 12. However, because the injector 104injects a precise amount of particulate matter into the airflow atapproximately the same velocity as the surrounding airflow, testingsystems 10 according to embodiments of the invention may be able toachieve uniform particulate distribution and velocity with far lessdistance between the injector 104 and the chamber 12. Testing systems 10according to embodiments of the invention may also be able to achievelaminar flow more readily than prior art systems. Moreover, the presenceof the particulate matter in the airflow may make it possible in atleast some cases to visually verify the existence of laminar flowentering the chamber 12 by looking through the window 52.

Additionally, because the injector 104 is positioned in the center ofthe delivery duct 18, rather than at the top or along one of the sides,it may be easier for the particulate matter to reach a uniform spatialdistribution in the airflow.

Another advantage of the particulate delivery system 26, and the system10 as a whole, is that by feeding a measured quantity of particulatematter into the delivery duct in a defined unit of time, the particulatedelivery system 26 makes it possible to calculate the concentration ofparticulate matter in the airflow at any given time. In someembodiments, the computing system 42, which may actively control theparticulate delivery system 26 or take input from its sensors, wouldmake these concentration calculations automatically and in real timeduring a test.

Particulate Matter Conveying System

As was described briefly above, particulate matter is conveyedpneumatically in fluidized form through the system 10. Overall, apneumatic conveying system is gated or valved so that the same pneumaticcomponents can be used to convey material either into or out of thesystem 10.

The following description focuses on the arrangement and components ofthe pneumatic conveying system. However, as those of skill in the artwill realize, in other embodiments, other methods may be used to conveymaterial through the system, including screw-driven conveyors andaero-mechanical conveyors. As one example of an alternative conveyingsystem, aero-mechanical conveyors that use a series of cable-connecteddisks within a pipe or tube, such as those sold by AEROCON (Belleville,N.J., United States), may be used to convey material.

With respect to the illustrated embodiment, particulate matter entersthe system 10 through the material input station 36, which is located inthe rear of the system 10, directly behind the chamber 12. As shown inthe elevational view of FIG. 2, the material input station 36 has areservoir 110 which is covered by a hinged cover 112. In order tointroduce particulate matter into the system 10, a user lifts the cover112 and deposits the particulate matter into the reservoir 110.

As with other elements of the system 10, the material input station 36includes user protection features that help to prevent user exposure toand inhalation of particulate matter. Specifically, the hinged cover 112is coupled to a switch, such that when the cover is lifted, the exhaustfan 64 located at the top of the material input station 36 is activated.The activated exhaust fan 64 draws air upwardly, through the filterelements 62, creating a negative pressure within the material inputstation 36 and drawing any particulate matter that may get into the airaway from the user. Of course, an external switch could be provided toactivate the fan 64, or it could be activated through the interface 44of the computing system.

FIG. 7 is an elevational view of the material input station 36,separator 94, and feed hopper 38, with the material input station 36 inpartial section. A pipe 114 leads from the reservoir 110 to theseparator 94 above the feed hopper 38. Located between the reservoir 110and the pipe 114 and in communication with both are a rotary valvefeeder 116 and an air inlet 118. As the feeder 116 gradually feeds theparticulate matter from the reservoir 110 into the pipe 114, a pump 120placed in fluid communication with the pipe 114 draws air into thesystem through the air inlet 118. The incoming air fluidizes theparticulate matter and allows it to be conveyed through the pipe 114 tothe separator 94.

Much of the rest of the pneumatic conveying system can be seen in theperspective view of FIG. 8, which shows the pneumatic conveying systemin isolation. Once the particulate matter has been injected into thedelivery duct 18 and brought through the chamber 12, it is collectedfrom the bottom 58 of the chamber 12 and the bottom spaces 76 of thefilter chamber 20 by a set of collection pipes 78, as was noted brieflyabove.

A set of gates 122, 124 direct the flow of the fluidized particulatematter. As was described above, dust is often recirculated throughoutthe duration of a single test, while sand typically is not recirculated.Therefore, dust is typically directed from the collecting pipes 78 backto the separator 94, where it is ultimately fed into the feed hopper 38and re-introduced into the delivery duct 18.

Once a dust test is complete, or after sand is collected in thecollection pipes 78, it is conveyed to the waste hopper 40. The wastehopper 40 includes an internal knockdown chamber that removes theparticulate matter from the fluidized stream by impingement on a plateor baffle. The air is then routed from the waste hopper 40 back into thesystem 10. The waste hopper 40 itself may be located outside of abuilding in which the rest of the testing system 10 is located, and isarranged to be “self-dumping,” such that material in the waste hopper 40can be easily loaded onto a truck or other conveyance for disposal.

In addition to the various filtration and separation elements employedby the testing system 10, the pump 120 has a secondary or safety filterelement 128 associated with it. The purpose of the safety filter element128 is to protect the pump 120 from damage in the event that airreaching and passing through the pump 120 is insufficiently filtered.

Methods of Operation and Testing

FIG. 9 is a flow diagram of a method, generally indicated at 200, ofoperating the environmental testing system 10 to conduct sand and dustenvironmental tests. Method 200 begins at 202, typically with the userloading the test piece into the chamber 12, and continues with task 204.

In task 204, the user enters basic test data into the computing system42, usually including the type of test that is to be conducted (sand ordust), the desired air velocity (e.g., in units of feet or meters perminute), and the desired particulate matter concentration. From thosebasic inputs, the particulate delivery system 26 calculates the weightof particulate matter per unit of time that is to be injected (e.g.,pounds or kilograms per hour). In some embodiments, rather than enteringspecific numerical setpoints for air velocity and particulate matterconcentration, the user may be permitted to select from a pre-programmedlist of testing options and protocols.

Method 200 continues with task 206. In task 206, the blower 46 is turnedon and set to move with an initial velocity (e.g., 10 Hz) in order tocirculate air within the system 10 for heating. Next, in task 208, thepneumatic gates 122, 124 are set for loading particulate matter into thesystem 10, and the user is prompted to load particulate matter.

The user then loads the particulate matter into the material inputstation 36. As shown in task 210 of method 200. As described above,while particulate matter is being loaded, the exhaust fan 64 isactivated to draw any airborne matter away from the user. Once materialis loaded, method 200 continues with task 212.

Task 212 of method 200 begins the process of bringing the temperatureand humidity of the system to the desired or specified conditions fortesting. In particular, task 212 is a decision task. If the airtemperature and humidity are not at the desired setpoints (task 212:NO),the heating element 90 is turned on and/or maintained in operation intask 214. If the temperature and humidity have reached their desiredsetpoints (task 212:YES), method 200 continues with task 216.

In task 216, if necessary, the pneumatic gates 122, 124 and otherelements are set to the settings that are to be used for the test. Next,in task 218, the blower 46 is ramped up to the velocity needed for thetest.

After task 218, the environmental testing system 10 is ready to conducta test. At that point, method 200 may pause until a user provides acommand or pushes a button to begin a test. Once the user initiates thetest, method 200 continues with task 220, in which the particulatedelivery system 26 begins to feed the particulate matter into thedelivery duct 18.

Once the test has begun, method 200 begins an iterative loop to monitortemperature, humidity, air flow, and blower speed. More particularly,task 222 is a decision task in which the computing system 42 checks tosee whether the temperature is greater than the desired setpoint. Insome cases, a threshold may be used, so that the actual determination iswhether the temperature is greater than the setpoint plus the threshold.For example, in one embodiment, the threshold may be about threedegrees. If the temperature is greater than the setpoint or the setpointplus the threshold (task 222:YES), method 200 continues with task 224,the cooling element 88 is activated, and the appropriate dampers 80, 82are actuated so that air flows into the heating and cooling duct 24. Ifthe temperature is not greater than the setpoint or the setpoint plusthe threshold (task 222:NO), method 200 continues with task 226. As anadditional consequence of task 222, if the dampers 80, 82 werepreviously actuated to move air into the heating and cooling duct 24,they may be actuated to move air through the main duct 22.

In task 226, the computing system 42 determines whether the air is toocold. More specifically, in task 226, the air temperature is checkedagainst the setpoint. If the temperature is less than the setpoint, orless than the setpoint plus a threshold (task 226:YES), then method 200continues with task 228, the heating element 90 is activated, and theappropriate dampers 80, 82 are actuated so that air flows into theheating and cooling duct 24. If the temperature is not less than thesetpoint, or less than the setpoint plus a threshold, method 200continues with task 230. As an additional consequence of task 222, ifthe dampers 80, 82 were previously actuated to move air into the heatingand cooling duct 24, they may be actuated to move air through the mainduct 22.

In task 230, the output of a sensor, such as a differential pressuresensor or anemometer, is checked to determine whether the air velocityis within defined limits for the test. If the air velocity is not withinthe defined limits or does not meet a setpoint (task 230:NO), thenmethod 200 continues with task 232, in which the blower speed isadjusted up or down to bring the air velocity to the desired setpoint orwithin the defined limits. If the air velocity is within the definedlimits and/or meets the appropriate setpoint (task 230:YES), method 200continues with task 234. In some embodiments, the rotational speed ofthe blower 46 may also be noted and recorded. Checking the air velocityand adjusting the blower speed if necessary during the test ensures thatthe system can compensate for variations in the performance of theblower 46. Data that correlates blower speed with air velocity can alsobe used to adapt an existing test standard or create a new one.

In task 234, the computing system 42 determines whether the humidity inthe system is appropriate. If the humidity levels are not within definedlimits (task 234:NO), the computing system 42 may pause the test, stopthe feeding of particulate matter, and wait for conditions to change, asshown in task 236, or may stop the test entirely. Pausing the test maynot be necessary in all embodiments; however, if the humidity is outsideof the specified ranges, the particulate matter may clump up orotherwise become non-uniform in its distribution. If the humidity iswithin defined limits (task 234:YES), method 200 continues with task238.

In task 238, the computing system 42 checks to see whether the testtimer has expired. If the test timer has expired and the test istherefore over (task 238:YES), method 200 completes and returns at 240.If the test timer has not expired, control of method 200 returns to task222, and method 200 continues.

During the test, a number of other conditions may result in the testbeing paused or terminated early. For example, if the particulatedelivery system 26 is not delivering particulate matter at theappropriate rate, the test may be paused or terminated.

Once the test is complete, the pneumatic gates 122, 124 may be set andthe pump 120 activated to move the particulate matter to the wastehopper 40, if necessary. With sand, this would generally be doneautomatically during the test; with dust, it may be performed eitherautomatically at the end of the test or manually after the test iscomplete.

Portable Testing Systems

As those of skill in the art will appreciate, in many cases, the testchamber 12 can be enlarged, and the other components of the system 10scaled appropriately to handle larger pieces that require sand or dustenvironment testing. However, there is a threshold beyond whichenlarging the test chamber may be impractical or impossible. For thatreason, environmental testing systems according to embodiments of theinvention may be made portable and, in particularly advantageousembodiments, modular.

A modular system is one in which the components of the system aredivided into discrete parts which can be easily assembled, disassembled,and interchanged for other, similar parts. There are any number of waysin which this can be done. One of the best-known examples of a modularsystem is the intermodal transportation system. An intermodal shippingcontainer is a standardized shipping container, typically made ofcorrugated, welded steel, used to bundle cargo into unitized loads.Typically about eight feet long, eight foot six inches high, and eithertwenty or forty feet long, intermodal containers have standard fittings(typically castings and twistlocks on the corners of the container, see,e.g., U.S. Pat. No. 3,027,025 to Keith W. Tantlinger, the contents ofwhich are incorporated by reference in their entirety) allowing them tobe stacked on cargo ships and transferred from those directly to a truckchassis or a cargo train.

In particularly advantageous embodiments of the invention, anenvironmental testing system may be made portable and modularized suchthat its systems fit into and are installed within intermodal shippingcontainers. In this way, a plurality of intermodal containers may beshipped to a particular location and stacked or otherwise assembled tocreate a complete testing system.

As one example of how such modularization is achieved, FIG. 10 is anexterior perspective view of a modular particulate delivery system 300,installed within a modified intermodal shipping container 302. Thecontainer has standard sets of doors 304, 306 on one end and on oneside. An air conditioning and dehumidifying system 308 is positioned onthe other end panel of the container 302, and a pair of air vents 310 isprovided on the other side of the container.

The modular particulate delivery system 300, contained within anintermodal shipping container 302, is thus transportable in any way thata standard intermodal shipping container would be, and includes thestandard castings 303 at the corners for attachment purposes. However,as those of skill in the art will realize, it may be necessary ordesirable to use the system 300 where cranes and other mechanisms formoving the container 302 are not available. For that reason, as shown inFIG. 10, the container 302 may be outfitted with wheels 307 attached tothe lower castings 303 and a tow bar 309, which would allow it to betowed into place. A set of leveling supports 313, typically two per longside of the container 302, ensure that the container 302 is fixed inplace and level while it is operating.

Externally, the particulate delivery system 300 includes a deliverynozzle, generally indicated at 312, connected to a set of piping ortubing 314. The piping or tubing 314 connects to an outlet 316 that isaccessible along the exterior of the container. Preferably, theparticulate delivery system 300 is made so that the castings,twistlocks, and other elements that allow the container 302 to be usedas an intermodal shipping container are retained. For that reason,elements like the nozzle 312 and piping 314 may be detached for shippingand the outlet 316 removed or capped as necessary. The exterior of thecontainer 302 may also include an electrical outlet or outlets forconnecting with external power. While not shown in the drawings, thecontainer 302 may have its own internal electrical power distributionsystem, including circuit breakers and other conventional elements.

Altogether, the particulate delivery system 300 performs the samefunction as the particulate delivery system 26—it supplies preciselymetered quantities of sand or dust at the appropriate velocity, in thiscase, through the nozzle 312. FIG. 11 is an interior perspective view ofthe container 302, taken from a perspective that is rotated with respectto that of FIG. 10. Within the container 302, the system 300 includesmany familiar elements, including a material input station 318 with thesame basic design and operator protection features as the material inputstation 36 described above. Particulate matter lands in a feed hopper319 in the lower part of the material input station 318 and is conveyedpneumatically from the feed hopper 319 via piping 320 to a feederassembly 322.

Also present to support the sand and dust delivery function are an aircompressor 330 and compressed air storage tank 332, and a desiccant airdryer 334. (The vents 310 on the exterior are in fluid communicationwith input and output ducts 331, 333 of the compressor 330.) An eye washstation 336 is also present, directly across from the material inputstation 318. The interior components of the air conditioning anddehumidifying system 308 are also present. Unless otherwise stated, allof these components may be assumed to function essentially as theircounterparts in the embodiment described above do. In contrast to theembodiments described above, the air conditioning and dehumidifyingsystem 308 primarily serves to maintain the appropriate temperature andhumidity conditions within the container 302 so that an operator canwork comfortably, and so that test equipment is not damaged by extremesof temperature and humidity. The container 302 may be insulated forequipment-protective and operator comfort reasons. As will be describedbelow in more detail, the system 300 generally supplies the particulatematter entrained in compressed air at ambient temperature (or whateverother temperature the air naturally achieves). If the test requires thatthe test piece be held at a particular temperature for a particulartest, other modular equipment may be used to provide and maintain theappropriate temperatures.

As can be appreciated from FIGS. 10 and 11, the components are installedin the shipping container 302 in a configuration in which they canactually be used, rather than in a shipping configuration, in which thecomponents would be packed together in a non-operational layout. Spacebetween the components allows a human operator to operate the system300, and components are arranged for operator convenience—like the factthat an eye wash station 336 is positioned directly across from thematerial input station where an operator would dump bags or sand ordust. The components would typically be bolted to the floor of thecontainer 302.

In some embodiments, additional operator protection and industrialhygiene features may be included. For example, the container 302 mayhave its own onboard, centralized vacuum system for cleaning andcontaining any particulate matter that may become loose within thecontainer 302. (As was described above, the material input station 318has its own draw fan and HEPA filter to keep loose particulate matteraway from the human operator while it is being loaded.) This may beparticularly helpful if the particulate matter in question is silica,which can have serious health effects if inhaled.

FIG. 12 is an elevational view of the feeder assembly 322 in isolation.Like its counterpart in the embodiment described above, air withentrained particulate matter enters a separator tank 324 located at thetop of the assembly 322. The separator tank 324 includes a set of bagfilters or other such filtering elements, which are not shown in theview of FIG. 12. (The agitator system 328 for those filter elements isvisible in the view of FIG. 11.) The filter elements knock theparticulate matter out of the air and send it into a conical hopper 338directly below the separator tank 324. A level indicator 339 provides anindication of the level of material in the hopper 338.

A rotary feeder assembly 340 feeds the material from the conical hopper338 to the components below. The rotary feeder assembly 340 may beeither belt-driven or direct-driven. Below the rotary feeder assembly340, the feeder assembly 322 includes an isolating valve 341, whichallows an operator to isolate the separator tank 324, the conical hopper338, and the rotary feeder assembly 340 to allow the feeder assembly 322to be filled, and for other purposes as necessary.

Once the particulate matter passes the isolating valve 341, it entersthe primary feeder 342, which is a loss-in-weight or loss-in-volumesystem that can precisely meter and dispense the particulate matter. Inthe illustrated embodiment, the primary feeder 342 is a screw-driven,pharmaceutical-grade machine that dispenses particulate matter from anoutlet 344 into a second conical hopper 346. As shown, the primaryfeeder 342 lies within an enclosure 348 to avoid disturbances andirregularities in the particulate matter supply. A Venturi valve 350lies below the second conical hopper 346 to inject the particulatematter into the air stream. With respect to the coordinate system ofFIG. 12, the compressed air supply from the compressed air tank 332enters the valve 350 from the left and a stream of compressed air withfluidized particulate matter exits to the right and flows to the nozzleassembly 312.

The nozzle assembly 312 may have a number of components itself,including a component to reduce static electrical charge, such as aCONVEYOSTAT static electricity eliminator 352 and a basket nozzle 354.Depending on the application, other elements may be attached to, or usedin association with, the basket nozzle 354. Alternatively, the basketnozzle 354 may be replaced by another, more suitable, type of nozzle, ifthe application requires it.

Thus, most of the components of the testing system 300 are very similarin form and function to the core components used to generate compressedair and meter and deliver particulate matter in the testing system 10described above. However, as those of skill in the art will appreciate,the modular testing system 300, as illustrated, lacks the heating andcooling and particulate matter recovery and recycling systems found inthe testing system 10 described above. The testing system 300 also lacksa high-volume air mover.

However, the advantage of the testing system 300 is that the operatorcan use whichever of those components are required for the particulartask or installation, and can connect additional modules if additionalcapabilities are needed. For example, if the goal of a particular testis to send sand or dust into the intake of a jet engine, it may besufficient simply to place the nozzle assembly 312 a prescribed distance(to ensure laminar flow) and send sand and dust into the engine intakeat whatever velocity can be supplied by the compressed air systemwithout a separate air mover. Of course, if high-volume, high-velocityair is required, a separate air mover module could be provided,typically installed, as described above, upstream of the nozzle assembly312 so that sand and dust do not foul the blades of the air mover.

Whereas the system 10 described above is a closed-loop system whereparticulate matter can be recycled through the system, the modularsystem 300 described here is, by itself, an open-loop system. Ifnecessary, another modular component downstream could collect andrecycle the particulate matter. One major advantage of the system 300 isthat pieces and equipment of arbitrarily large sizes can be tested,without regard to the maximum dimensions of a test chamber.

While the invention has been described with respect to certainembodiments, the description is intended to be exemplary, rather thanlimiting. Modifications and changes may be made within the scope of theinvention, which is defined by the appended claims.

What is claimed is:
 1. A modular particulate matter environmentaltesting system, comprising: a shipping container including: a materialinput station adapted to accept particulate matter; a particulate matterfeed assembly in fluid communication with the material input station toreceive the particulate matter, the particulate matter feed assemblybeing adapted to meter and deliver defined amounts or concentrations ofthe particulate matter to a feed valve; a compressed air supply systemsupplying compressed air to the material input station and theparticulate matter feed assembly; and a nozzle assembly coupled along anexterior sidewall of the shipping container and receiving compressed airwith entrained particulate matter from the feed valve; wherein thematerial input station, the particulate matter feed assembly and thecompressed air supply system are positioned within the shippingcontainer in an operational configuration.
 2. The modular testing systemof claim 1, wherein the material input station comprises an inputsection and a hopper.
 3. The modular testing system of claim 2, whereinthe input section includes a lid, a negative draw fan, a filter, and aswitch that activates the negative draw fan when the lid is opened. 4.The modular testing system of claim 1, wherein the particulate matterfeed assembly comprises: a separator that receives a fluidized mix ofthe particulate matter and compressed air from the material inputstation and separates the particulate matter from the compressed air; afeeder that receives the particulate matter from the separator anddispenses a metered amount or concentration of the particulate matter;and the feed valve, which receives the metered particulate matter and afresh supply of compressed air and entrains the metered particulatematter in the fresh supply of compressed air.
 5. The modular testingsystem of claim 4, wherein the feed valve is a Venturi valve.
 6. Themodular testing system of claim 1, wherein the compressed air supplysystem further comprises: a compressor; a desiccator connected to thecompressor; and and a storage tank that receives and stores compressedair.
 7. The modular testing system of claim 1, wherein the nozzleassembly comprises a nozzle.
 8. The modular testing assembly of claim 7,wherein the nozzle comprises a wire basket nozzle.
 9. The modulartesting system of claim 7, wherein the nozzle assembly further comprisesa static electricity reducer upstream of the nozzle.
 10. The modulartesting system of claim 1, wherein the nozzle assembly is coupled to anoutlet along the exterior sidewall.
 11. The modular testing system ofclaim 10, further comprising piping coupled between the outlet and thenozzle assembly.
 12. The modular testing system of claim 1, wherein theshipping container comprises an intermodal shipping container.
 13. Themodular testing system of claim 12, wherein the intermodal shippingcontainer comprises a set of wheels or casters.
 14. The modular testingsystem of claim 12, wherein the intermodal shipping container comprisesa set of external leveling supports.
 15. The modular testing system ofclaim 12, wherein the intermodal shipping container comprises a tow bar.